1. Field of the Invention
This invention relates to electronic circuits, and more particularly, to storage circuits.
2. Description of the Related Art
During the design of a computing device (e.g., traditional computer, notebook, server, handheld or other mobile device, etc.) or other processor-based system, many design factors must be considered. A successful design may require several tradeoffs between power consumption, performance, thermal output, and so forth. For example, the design of a computer system with an emphasis on high performance may allow for greater power consumption and thermal output. Conversely, the design of a portable computing device that is sometimes powered by a battery may emphasize reducing power consumption at the expense of some performance. These same factors may be considered when designing the individual IC's to be used in the computer system.
One commonly used method of controlling power consumption is the use of power-gating. In a power-gated circuit, one of the voltage planes (e.g., supply voltage or ground) is a virtual voltage plane that is coupled to a corresponding actual voltage plane through a power-gating device (e.g., a transistor). When the power-gating device is active, power may be provided to or removed from by respectively activating or deactivating the power-gated circuit.
Power-gating may be used in many types of processor-based systems. Circuits may be divided into various power domains or functional units, and these may be powered on and/or off independent of other power domains/functional units. In some cases, where information is stored in circuits of a functional unit, the information may be written to another storage device prior to powering down the functional unit.